I have a big discussion about what type of voltage regulators should I use. Here is some things I have found.
A arduino UNO board from adafruit uses the next:
- NCP1117ST50T3G - LDO Voltage Regulators 5.0V 1A Positive
- AP2112K-3.3TRG1 LDO Voltage Regulators 600mA CMOS LDO 50mA 3.3V 250mV
Audio amplifier from Adafruit:
Other Radio board from adafruit uses:
LoRa board from adafruit:
Featured LDO’s
- For large step-down and low current -> MIC5225
- Low dropout, available for a long range of voltages and also adjustable option
- AP2112K
- 600mA
- 3V3, 1.8V, 1.2V, 2.5V, 2.6V
- In general is common to find the SOT-223-3 for a long range of voltages, you is possible to use a generic one
- TPS796xx Ultralow-Noise, high PSRR, 1A output
Featured Buck DCDC
- TPS62291DRVR 3.3V 1A Output
Featured Boost DCDC
- TPS61023DRLT Used for batteries, can be used for different range of voltages, it can gives the 5V output.
Buck-Boost VS LDO
You should chose BUCK BOOST over LDOS for:
- Energy efficient applications
- Heat Dissipation
- Large Step-Down Voltage Requirements
- High current applications
However LDOS:
- Simpler to use
- Less noisy
Charge pump vs inductor-based converters
There is a type of DC-DC that are called charge pumps that use capacitors instead of inductors:
- They dont generate magnetic noise, that is important for EMI
- They are common on low current.
- They are simpler than inductor-based regulators
However the DCDC with inductor can be more efficient, less ripples and handle more load. Also there is less available charge-pumps than inductor-based DCDC.
- A recommended charge-pump could be LM2665
Rule of thumb
I have checked a bunch of design with microcontrollers and these and the formula is the same:
- Use the 5V from the USB (or the battery) and put a LDO to generate the 3V3
- With this design is not necessary to buck or anything. All the devices should be capable to run with 3V3, and if you need more they should be capable to run with 5V or the battery voltage.